Apparatus for drawing seamless cans



June 1, 1954 M. E. MOORE APPARATUS FOR DRAWING SEAMLESS CANS 5Sheets-Sheet 1 Filed May 20, 1950 INVENTOR. iflark 9 /7Z0076 BY June 1,1954 M. E. MOORE 2,679,816

APPARATUS FOR DRAWING SEAMLESS CANS Filed May 20, 1950 5 Sheets-Sheet 2ilzczr'k '8. [Icons June 1, 1954 M. E. MOORE 2,679,816

APPARATUS FOR DRAWING SEAMLESS CANS Filed May 20, 1950 5 Sheets-Sheet 5June 1, 1954 M. E. MOORE 2,679,316

APPARATUS FOR DRAWING SEAMLESS CANS 5 SheetsSheet 4 Filed May 20, 1950 IN VEN TOR.

i fczr 5. Wanna June 1, 1954 E, MOORE 2,679,816

APPARATUS FOR DRAWING SEAMLESS CANS Filed May 20, 1950 5 Sheets-Sheet 5.511 2:92 JZzm INVENTOR.

Patented June 1, 1954 APPARATUS FOR DRAWING SEAMLESS CANS Mark E. Moore,Chicago, Ill., assignor to Williston Seamless Can (30., Inc., Williston,N. Dak., a

corporation of Delaware Application May 20, 1950, Serial No. 163,117

1 Claim. 1

The present invention relates to apparatus for drawing seamless cans,and is particularly concerned with improved devices by means of which.seamless cans made out of suitable metal, such as steel, aluminum,brass, copper, or any other suitable material, may be drawn fromcircular discs in a single stroke.

One of the objects of the invention is the provision of improvedapparatus by means of which seamless cans may be drawn more quickly andmore economically than by the methods of the prior art, for the reasonthat the present apparatus requires a single stroke with no intermediatehandling of the product so as to reduce the labor and increase theoutput.

Another object of the invention is the provision of an improved dieconstruction by means of which seamless cans may be drawn at a singlestroke and discharged from the machine at a high rate of production,such as, for example, about fifty cans per minute.

Another object is the provision of an improved die construction whichhas novel methods of lubrication, and otherwise reducing the frictionbetween the can parts and the parts of the die so that a maximum numberof perfect cans may be drawn with a minimum number of imperfect ortorn'cans.

Another object is the provision of improved apparatus by means of whichthe amount of power required to operate the dies is substantiallyreduced, while still forming substantially perfect seamless cans at asingle stroke and at a high rate of production per minute.

- Another object is the provision of improved apparatus for drawinseamless cans which involves a plurality of successive operations uponthe blank or can, but in which these operations are so quickly performedin succession that the metal of which the can is formed is still hotfrom the first and earlier operations, when the second or succeedingoperations are performed, so that the metal does not have an opportunityto become hardened by cooling in between operations; and the work, whichis performed in drawing the can and which is ordinarily dissipated inraisin its temperature, is greatly reduced in its total amount so thatcans may be drawn more easily with the expenditure of less power.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which similarcharacters of reference indicate similar parts throughout the severalviews.

Referring to the drawings of which there are live sheets accompanyingthis specification,

Fig. l is a side elevational view of the press equipped with the die andother apparatus embodying the invention;

Fig. 2 is a vertical sectional view taken on the plane of the line 22 ofFigure 1;

Fig. 3 is a front elevational view of the press of Figure 2;

Fig. 4 is a fragmentary vertical sectional view on a larger scale,showing the parts of the die of Figure 2 on the plane of the line 4-4 ofFigure 2, looking in the direction of the arrows and showing acompletely formed can at the time of its discharge from the inner postof the die;

Fig. 5 is a fragmentary sectional view taken on the same plane as Figure4, With the inner post of the die in elevation, showing the parts asthey appear after a disc has been fed to the die but before it isgripped by the pressure pad;

Fig. 6 is a view similar to Figure 5, showing the seamless can in thecourse of its formation, at the time when the inner post of the die hasreached the end of the sleeve or punch of the die and the blank has beendrawn entirely out of the space between the pressure pad and the face ofthe die;

Fig. 7 is another view similar to Figures 5 and 6, showing a seamlesscan in the course of its being drawn and showing the action of the innerpost-in the formation of the can after it has passed the lower end ofthe sleeve or punch;

Fig. 8 is a view similar to Figures 5, 6 and '7, with the parts of thedie in the position which they assume when the seamless can has beenwholly formed, and the lower forming die has also come into engagementwith the bottom of the can to shape the bottom as desired in cooperationwith the end of the inner post; and

Fig. 9 is a diagrammatic view showing the conduits and elements requiredfor the hydraulic operation of such a die.

Referring to Figs. 1 to 3, the present apparatus is shown in connectionwith a hydraulic press, indicated in its entirety by the numeral 2; butI desire it to be understood that the die can be operated mechanicallyas well as hydraulically.

The press preferably includes a suitable framework, which may consist ofa housing 25 joined at the top by horizontal frame portions 22, andjoined at a point above the bottom by a bed member 23, which isrectangular in shape and may be square.

The top frame members 22 support a cross head plate 24, against whichthe hydraulic cylinders may react, and to which they may be attached.This framework may be covered by means of a suitable housing 25,provided with lateral windows 26, 2! for access to the parts of the die.

The housing is generally rectangular, but may have a pair of laterallyprojecting lower diagonal flanges 28 for housing the discharge openingwhere the finished cans are discharged.

All of the fixed parts of the framework and housing may be constructedout of suitable steel, and may be secured together by suitable bolts orother fastening means, but are preferably welded together to provide arigid frame.

Referring to Fig. 4, the movable parts of the die are the pressure pad29, the sleeve punch 30, and the inner post 3!. Each of these ispreferably provided with a separate mechanical or hydraulic means forthe application of pressure and for moving these elements.

The pressure pad has a minimum amount of movement, moving upwardly onlysufi'iciently to admit the disc-shaped blank 32 (Figure 1) and,therefore, the pressure pad is actuated by means of hydraulic cylinder33, which is relatively short but powerful.

The plunger or piston 34 of this hydraulic cylinder is connected bymeans of a pin and slot 35 to a pair of levers 36, the opposite end ofwhich is pivoted at 31 on the frame. Levers 36 are pivotally connectedat 38 to connecting links 39, the lower ends of which are pivotallyconnected to the pressure pad at 40.

Thus the hydraulic cylinder 33, which is carried by cross head plate 24,is adapted to move the pressure plate 29 upward and downward; and whenthe pressure plate is in its lowermost position it is adapted to place aheavy pressure on the blank 32 to hold it against wrinkling as the blankis drawn from the flat condition and shaped into a can.

For example, the pressure in pounds per square inch placed by thepressure plate upon the blank may be about 100 lbs. per sq. in. Thepressure varies, depending upon the thickness of the can and thecharacter of the material of which the can is to be made, and thisexample is given as a suitable pressure for cans made of 30 gauge steel.

The sleeve punch 30 may be actuated by means of the hydraulic cylinder 4I, carried by cross head plate 24, and having a plunger or piston rodwhich is pivotally connected at 42 to a pair of links 43. The links 43are pivotally connected at 44 to a pair of levers 45, the opposite endsof which are pivotally mounted on the frame at 46 on a suitable pivotbracket 41.

The levers are pivotally connected at 48 to a pair of downwardlyextending links 49, which have their lower ends pivotally connected at50 to a guide plate 5| which supports and guides the sleeve punch 30.

The pressure pad 29 also includes a suitable guide plate 52. These guideplates may be rectangular in shape, and are preferably square and areprovided at each of their four corners with upwardly or downwardlyextending tubular guides 53 and cylindrical bores 54.

The bed 23 of the press supports a suitable base plate 55 for the dieassembly, which base plate carries four upwardly extending, equallyspaced and parallel cylindrical guide rods 56. The guide plates 5| and52, which support the sleeve punch 30 and pressure pad 29 are slidablymounted on the rods 56, and the elongated surfaces in the bores 54engaging the rods guide the plates with a minimum possibility ofbinding.

The inner post 3| may be actuated by the cen- Cir trally locatedhydraulic cylinder 51, carried by the cross head plate 24 and locatedbelow at its center between the pairs of levers 36 and 45.

The piston or plunger of the hydraulic cylinder 57 is provided with aconnecting rod or connecting rod portion 58, which is fixedly secured tothe inner post 3|. For example, connecting rod 58 may have a reducedthreaded portion 59, received in a threaded bore 60, and driven homeuntil the annular shoulder 6| on the connecting rod 58 engages the upperplane end of the inner post 3|. Thus the inner post is adapted to bemoved and it has pressure applied to it by the hydraulic cylinder 51.

The range of movement of the sleeve punch 30 is determined by itslength, which in turn is determined by the length of the can to beformed; and the pressure applied to the sleeve punch by means ofhydraulic cylinder 4| varies with different sizes of cans and the gaugeand character of metal employed for the can.

The inner post 3| has the greatest range of movement since it movesfirst with the sleeve punch 30, and later moves down beyond the sleevepunch 30 to complete and discharge the can.

Therefore, the hydraulic cylinder 51 is longer and like the others thepressure applied depends upon the size of can, character, and gauge ofmetal.

Referring to Figure 9, this is a diagrammatic illustration of the oiland air circuits for the hydraulic cylinders for lubrication and forcompressed air supply. For purpose of illustration the valves 62 areshown as being operable by means of suitable cams 61-H, all of which maybe mounted upon a single timing shaft.

However, I desire it to be understood that the valves may be actuatedautomatically by the movement of the parts, such as the pressure pad,the sleeve punch, or the inner post, so that the arrival of these partsat predetermined positions determines the actuation of the valves formoving the next part or parts in the cycle of operation.

Thus the mechanism may be arranged so that when the hydraulic cylinderapplies pressure to the blank disc this also actuates the valves 63 and64 to cause them to begin the movement of the inner post and sleevepunch. Therefore the cams are merely used for purpose of a simplifiedexplanation.

The system includes an oil sump 72 and an oil pump 13, having its inletextending into the oil of the sump and discharging oil under pressure toa surge tank 14. The surge tank has its discharge pipe 15 depending intothe oil which has entrapped air 16 in the space above the oil, so thatthe compressed air in the surge tank provides a supply of oil at asubstantially constant pressure.

The oil supply pipe I5 has branches leading to the three valves 62-64,which have branch return pipes connected to an oil return pipe11,-returning the used oil to the sump. The valves 62-64 controlconduits 18 and 79, and 8|, and

82 and 83, leading to the opposite ends of the hydraulic cylinders 33,4t and'51, respectively, so that the valves 62-64 may supply oil underpressure to either side of the piston in each hydraulic cylinder to movethe parts in either direction as required in the cycle in operation ofthe die.

The diagram, Figure 9, also includes valve 65, controlled by cam 10, forcontrolling a conduit 84, leading to a source of lubricant underpressure to supply lubricant to the die. The valve 66,

controlled-by cam H,- controls a conduit 85, providing a supply ofsuitable air pressure, for the purpose of discharging the cans from thedie and for assisting in the drawing of the cans during the cycle ofoperation of the die.

Lubricant and air supplies are connected by suitable flexible pressureconduits 86, 81 to the inner post 3|, at the threaded bores 88 and 89 atthe top of this post. For example, the threaded bore 89 may be forlubricant, and it may communicate with the longitudinally extending boreor conduit 90, which terminates at the lower end of the post 3| in asuitable outlet 9 I, controlled by a ball check valve, spring pressedinto closed position by spring 93.

Check valve 92 prevents lubricant or air from going backward in theconduit 90. The conduit 90 preferably communicates with a transverselubricant conduit 94, which may have a plurality of outlets 95, locatedjust below the piston rin s 96. v

The piston rings are mounted in suitable piston ring grooves in thecylindrical inner post 3| for preventing the loss of lubricant or airupwardly through the clearances between the post 3| and sleeve punch 30.

The threaded bore 88 leads to a longitudinally extending conduit or bore91 for air, which is provided with a discharge opening 98 at its lowerend, controlled by a ball check valve 99, urged into closed position byspring I00.

Check valve 99 aids in maintaining suitable air pressures at times whenthe air has been shut off at the air valve. The structure of the dieassembly is preferably as follows: The bed 23 of the press is providedwith a central bore IOI, bordered by a depending tubular portion I02,through which the finished can passes to be discharged. The can inFigure 4 is indicated by I03.

The depending tubular formation I02 supports a can discharge guide I04,comprising a partially cylindrical body I05, provided with laterallyprojecting, parallel guide flanges I06. The can discharge guide issecured at its attaching flange I01 to the tubular formation I02 byscrew bolts I08.

The can discharge guide I04 has an inner cylindrical surface providing acontinuation of the cylindrical bore I09, which acts as a guide for thelower pressure plunger IIII, which cooperates with the inner post 3| toform the lower end of the can. The lower end or bottom III of the can ispreferably formed with an annular, outwardly projecting, pressedcorrugation II2, taking the form of an inner groove partially circularin cross section and an outer rib.

The bottom I I I is also preferably formed with a rib I I3, having aneasy bend, which is partially circular in cross section and whichextends all around the lower edge of the seamless can projectingdownwardly.

The rib II3 approximates in shape and structure the seam which nowappears on the bottoms of seamed cans, so that the present seamless cancan be gripped more readily or centered and held by can handlingmachinery, such as a can opener. The upper end of the lower plunger His, therefore, complementary in shape to the lower surface of the bottomIII of the can.

The lower end N4 of the inner post 3| is complementary to the inside ofthe bottom of the can II I. Therefore, the bottom of the inner post isflatand plane except for the depending annular l sua. '1

The lower plunger I I0 may also be actuated by suitable mechanical orhydraulic means, and it moves up in the cylindrical bore I09, which hasa suitable pivoted stop member III pivotally mounted in a slot II8 andhaving curved stop surface II9 for engaging the bottom of each can anddeflecting it out of the housing I05 intothe rectangular trough I20.

The stop member II'I pivots by gravity to the position of Figure 1 orFigure 4, but plunger IIO cams against the beveled surface I2I to movethe stop member out of the bore I09 and out of the way of the plunger II0 as the plunger comes An upward extension I22 on stop member II'Iengages the outside of housing I05 and prevents the stop member II! frompivoting farther in a counterclockwise direction from the left. Adepending tail I23, below the point of pivot I24, prevents stop memberII! from moving too far in a clockwise direction. I

The die supporting plate 55 is suitably secured to the bed 23 byadjustable bolts, not shown, so that its central cylindrical bore I25may be centrally located above the bore IOI. Base plate 55 has aconcentric, circular recess indicated by the annular shoulder I26 forseating the die body I21 in concentric relation to the base plate 55.

Die body I21 may be made of soft steel and comprises a cylindrical metalmember formed with a cylindrical bore I28, an annular shoulder I29 and acounterbore I30. Counterbore I30 has suitable clearance with respect tothe formed can and is for passing the can and the inner post whichsupports the can.

Cylindrical bore I28 is for receiving the hardened steel die member I3I,which is tubular in shape and has an outer cylindrical surface I32fitting in bore I28, with a plane surface engaging the annular shoulderI29.

Hardened die member I3I has a radial pressure flange I 33 seated in ashallow circular recess I34 in the die body I2I to hold the hardened diemember I3I in concentric position. Hardened die member I3I is held inits bore I28 by bolts. Ring I35 has an overhanging annular shoulder I36engaging the top of the radial flange I33 at its outer edge, and servesto locate the blank.

Retaining flange I31 is preferably beveled at I38 on its inner uppercorner, but has an inner cylindrical portion I39 which locates and holdsthe blank disc 32 in proper position. As seen at I40 (Fig. 1), the upperretaining flange I31 is cut away on the feed side of the die tofacilitate the entrance of the blank discs 32 from the right in Fig. 1.r

' A suitable feed mechanism, generally indicated at I4I, includes astack of discs I42 and a chain drive I43, the driving lugs I44 of whichproject upwardly far enough to engage only one disc 32 and move it tothe left, where its motion is continued by lubricating rollers I45, oneof which dips into a lubricant reservoir I46 to lubricate the blank.

: Any type of-feed and lubricating mechanism may be employed, and thatshown is merely dia-i clearance with respect to the external cylindricalsurface I48 of the sleeve punch 30, which provides space for thecan-blank and is proportionate to the thickness et the 1 blank at 'thetime it -is partially formed and locatedon "the outside of the sleevepunch 30. l

Belowthe cylindrical-bore portion I' I'I there is an-annular lubricantgroove I49 which commum'eates with a throu'gh'bore I 50 in-ithe hardeneddie member I 3|, which in turn communicates with -an annular groove IBIand a cond'uit 152' in the antibody I21.

*A-branoh conduit from the oilsupply conduit may-alsobe-conneoted-tothis conduit I 52. The conduits Just referred to supplylubricant to the outside of the partially formed can, the lubricantfinding its way i upward into -the bore -I '41; outside of the can anddownwardover the frusto conical surface I53, in the"- hardeneddie memberI3I, which is immediately -belowtheannular lubricant conduit I49.

"The frusto-conicial surface I53 in the die member I3I is of the sameangularity as the beveled surface I 54-on the lowenend of the sleevepunch 30. Above the cylindrical -bore "I4|, in thedlie member -I 3 Ithere is an annular rectangular groove which may serve as a lubr'icantreservoir for receiving excess "lubricant;-andabove the annular groove1'55 thereis a cylindrical bore I56 of slightly greater-diameter thanthe'bore I41. Bore I56 provides relief about the partially formed canblank as it is drawn down into the roundopening' of the-"die member I 3I At-its upper-"end theopening-in the die member "I3I -is provided witharounded corner I51, which-has a clearancewith respectto the sleeve punch30, depending upon 'the-amount'ofdraw that is to be'accomplishedin thecan blank at this point.

From the corner -'|5'| the-opening in the die member I3 I becomesgradually larger, having a frusto-conical portion l58down to the-boreI56. Below the I rusto-conical surface I 53, at the lower endof thehardened die member I3I, this member is provided-witha round here|59-leading from -a rounded, annular-"corner I60, and the round bore I59tapers upwardly and substantially frustoconicar and larger at the bottomto providea relief about the can wall -after it has been'drawn overthecorner I60 of thediem'ember 'I3 I.

- The lower end of the 'die member -'I 3 I may be plane at thelower endI6I, fitting in the bore I28 against the annular shoulder I29. Thesleevepunch 30 comprises a hardened steel tubular member having thecylindrical outer-surface I48 and also-having a cylindricalinner bore62.

The outer cylindrical surface I48 has a; sliding fit-with :the-b'ore'I63 extending through the pressure -pad Zeand itssupporting plate 52.-At its upper :end, above the pressure pa'dsupporting plate'52; punchsleeve 30 has a radial supporting flange I64 provided with threadedbores for receiving the screw bolts 1'65; by'means of which the sleevepunch is secured to the guide plate 5 I Guide plate 5| has a borefitting about the upper tubular end of 'the sleeve puneh -flxand guideplate'S'I- hasacounte'rbore I'G'Ffor receiving the radial flange I 64.The internal bore I62 oi' the sleeve punch 30 is cylindrical and has asliding fit with respeet totheinner post 3 I. V

The inner post- 3| eomprisesa hardened and solid cylindrical steelmember attached at its upper end to the connecting rod orjplungerf58.and provided at its lower enewamhe formations for shaping thebottom ofthe can.

Referring now to Figures 5 to 8-,tl'1ese are views showingthe=method=o1makingseamlesscans in azs'ingle stroke operation.

In'Figure 5 the innerpost- 3-I 'the'punch sleeve 30, and the pressurepad'29 have all been raised above the die member lfl, and acircularste'eldisc or blank has been fed into the recess which is bounded by theannular-wall- I39. The pressure pad 29'descendsaga-inst the blank 32first-and clamps it firmly against the die memberl 3 I to hold the blankagainst wrinkling as it is drawn into can shape.

In the next stepafter this the inner post 3| and sleeve punch tlldescend toge'the -the lower end I 4 of the'inner'post beingsubstantially flush with the lower end I68 of the sleeve punchSIl.The-sleeve punch and innerpost act as one solid body-engaging the blankdisc 32 and drawingit downward over'the roundedcorner I5'I,*forming aroundpartially formed can'body of the'shape shown in Figure" 6.

As the inner post and sleeve punch descend the edge of the blank 32 isdrawn inward underneath thepressure'pad and gradually diminishes indiameter until it has been entirely drawn'from beneaththe pressure'pad."Whenthe inner po'st 3| and sleeve punch 3|] have arrived at theposition of'Figure 6 and are ready'for the second drawing operation, allofthe'blank should havebeen drawn out from beneath the pressure pad.

The next step in the formation of the can'is its further reductioninsize from the'enlarged cylindrical shape 'of Figure 6, to the smallercylindrical size of the internal post 3|. This is accomplished bystopping the sleeve punch 30 in the position shown Figure 7 and holding"it there with hydraulic pressure while the inner post 3| continues tomove downward to draw the partially formed can wall over the annularcorner I60, further reducing it insize and elongating the can, a part ofwhich has already been completed in Figure 7.

The'inner'po'st 3| continues to move downward until the entire can haspassed the annular corner I60, and the entire can has been drawn intothe smaller cylindrical shape whichis complementary to the inner post3|.

During all of this time the lower bottom shaping plunger III] hasbeenrising, and immediately after the cylindrical wall of the canhas reachedits final shape in-Figure 8, the bottom shaping plunger I In comes intoengagement withvthe bottom of the can and the bottom is shaped betweenthe lower plunger III) and theupper inner post 3|, as shown Figure 8.

Thereafter the bottom plunger III] is withdrawn-and the can is forced onthe lower end of the inner. post 3I by air pressure, but air pressure isnot merely'used for discharging the can, and is, like the lubricant,constantly applied to the inner post'discharging out of its lower endinto the inside of the partially formed can while the die-is. doing -itswork.

The air on' the' inside of the can blank'32, in Figure 6, providesa-powe'rful internal pressure which tends to expand the can slightly andto separate the can walls from the post" 3I'by fluid air so-that the cancan be drawn more easily. While the can is being further elongated anddiminished insize, as shown in Figure .7, the air under pressure comesout'of'the lower end of the inner post 3| into therein 32 and leaksupward along the sideof the partiallyformed can.

The air cannot pass'the piston ringsilt and, thereforeflit tendsto"follow*the inside of the can wall and to go between the can andtheoutside of the sleeve punch 30 in Figure '7, tending to space thesetwo surfaces and to enlarge the can so that it is drawn more easily.

When the can is completely formed, as shown in Figure 8, the airpressure still tends to enlarge the can and to permit its discharge ohthe lower end of inner post 3| with greater facility, also acting tomake the cans slide off.

The lubricant which is suppliedthrough the conduit 90 is delivered firstat points just below the piston rings from whence it is forced downwardbetween the inner post and the punch sleeve 30, and leaks upward aroundthe inner sleeve punch 30 inside the can wall.

Other lubricant is supplied outside the can wall at the annular grooveI49, lubricating the outside of the can wall just before it is drawnover the annular corner I611. The prelubrication of the blank at its topand bottom as it is fed into the die proviles lubrication between theblank andthe pressure pad, and between the blank and the top of thehardened die member I3l.

When the can has been completed, as 'shown in Figure 8, the lubricant ispreferably shut off by its valve to prevent its loss, and as. soon asthe can has been discharged from the end of the inner post the airsupply is shut off until the die parts have again been elevated to theposition of Figure 5, and until they have been caused to descend intoengagement with another blank 32. Then the air and the lubricant mayboth be turned on before the die operates.

My method of making seamless cans may be briefly summarized as follows:

Circular blanks of sheet metal are first punched out of the sheets andarranged in stacks, and they are fed from the bottom of the stackthrough an oiling device which coats the top and bottom with oil as theyprogress toward the die assembly.

The disc-like blanks are fed one by one into the die assembly betweenthe pressure pad and the female die member, and they are first clampedin flat condition against the upper plane surface of the female die bythe pressure pad.

The location of the blank at the time is concentric and is determined bya complementary concentric recess on the upper face of the female diemember. The blank is subjected to sufficient pressure at its planeportions during the drawing operation to prevent wrinkling.

The next step comprises the drawing of the plane blank into enlargedcylindrical form by means of a composite die body comprising an internalcylindrical post and an external cylindrical sleeve until the plane partof the blank is wholly withdrawn from beneath the pressure pad andshaped into cylindrical form.

The next step comprises the continuance of the drawing operation bymoving the inner one, that is the cylindrical inner post of thatcomposite body onward in the same direction, drawing the partiallyformed can over an annular forming surface into a smaller bore whilelubricating the wall of the can on the outside and the inside,,and atthe same time applying air pressure to the inside of the can wall duringits successive forming operations. lhe oil is, of course, supplied at ahigher pressure than the air, which oil pressure determines the amountof lubrication; proper amount of lubrication is determined by trial anderror and by inspection of formed cans.

The application of the air pressure causes air to leak along the insideof the can wall, separat- 10 ing it slightly from the forming andsupporting die parts on the inside of the can, expanding the canslightly due to the air pressure filling the inside of the can with thefluid air so that it can be drawn moreeasily with less power and less,change of tearing.

The latter forming operation continues until the parts of the partiallyformed can have been wholly drawn off the outside of the punch sleeveinto the smaller bore and shaped to the external cylindrical surface ofthe inner'post, whereupon a lower forming die member is brought intoengagement with the bottom of the can to shape the bottom of the can.

In this 1atter step the bottom of the can is simultaneously formed witha re-enforcing annular ridge and with an annular ridge adjacent the canwall to give it a stable lower supporting surface. When a supportingannular ridge is provided at the outer lower wall of the can, this ismore easily made stable and in the same plane than the can is apt to beif its bottom were perfectly plane.

Finally, the formed can is released by the lower die and subjected tointernal air pressure while it is on the upper die or internal post toexpand the finished can and move it off the end of the post by thethrust developed by air pressure. The can is then guided into a troughwhich may lead to a conveyor or conductor for cans.

It will thus be observed that I have invented an improved apparatus bymeans of which seamless cans may be drawn at a single stroke by means ofdie parts which first form the can into a larger cylindrical shape andthen continue to draw it into longer and thinner cylindrical shape,after which the bottom is preferably formed into a definite shape.

By means of my methods and apparatus, suitably controlled, more cans perminute can be made than with any other method and also less labor isemployed. Every time a can has to be handled, either manually or bymachine, to place it on a new die the cost is increased and this isavoided by means of my apparatus which forms the seamless cans at asingle stroke.

I am aware that seamless cans have been previously made by means of aplurality of different operations upon a plurality of different dies ina plurality of steps, but in the devices of the prior art theintermediate products have been permitted to cool before they were actedupon by successive dies or operations. This alternate heating andcooling not only involves separate handling of the intermediatecontainers by the operators, but such methods harden the metal andrequire the expenditure of more power in the drawing of the can, thispower being dissipated in the act of heating the can a plurality oftimes, whereas according to my method the blank or container issubjected to a plurality of successive operations immediately followingeach other while the can metal is still hot, so that the metal does nothave a chance to cool and toughen and less power is dissipated in theform of heat.

While I have illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention, and I do not wish to be limited to the precise details ofconstruction set forth, but desire to avail myself of all changes withinthe scope of the appended claim.

Having thus described my invention, what I per clamping surface, a bore,and a counterbore,

with a first annular drawing shoulder at the upper end of said bore, anda second annular drawing shoulder between said bore and counterbore, asleeve punch in said bore and terminating in a bevelled lower edge, saidbore having a complementary bevelled surface above said second drawingshoulder, a pressure pad surrounding said sleeve punch above saidclamping surface, a male post slidably mounted in said-sleeve punch tobe received in said counterbore, three hydraulic cylinders and pistons,including a first piston connected to actuate said pressure pad, asecond piston connected to actuate said sleeve punch,"and a third pistonconnected to actuate said male post, said male post having a conduit forconducting air under pressure to the lower end of saidpost; and having asecond conduit for conducting lubricant under pressure to the interiorof said sleeve punch, said second conduit dischargingin: said sleevepunchbelow a plurality of piston rings:

carried by said male post and below the top .of said sleeve punch, saidfemale diehaving a third conduit for lubricant under pressure,discharging above its bevelled surface and second drawing shoulder, saidfirst piston clamping the edges of a circular blank against said femaledieto 12 prevent wrinkling. said second and third pistons advancingsimultaneously to draw said I blank over said first shoulder to form alarge cylindrical container, and said third piston advancing said malepost thereafter in said sleeve punch.

to draw said container over said second drawing shoulder, while .saidcontainer is lubricated inside and out and subjected to expanding airpressure, the said container passing through said female die and beingdischarged from the male post by internal air pressure.

References Cited in the file Of this patent UNITED STATES PATENTS NumberName Date Re.'20,009 Hothersall June 16,- 1936 6043056 Leavitt May '17,1898 760,921 Rigby May 24,1904 1,431,175 a, Ogden et al; Oct. 10, 19221,439,352 Ash etal. Dec. 19,1922 1,486,746 Heisel Mar. 11, 19242,289,199 Klockei July'7, 1942 2,292,462 Milford Aug. 11, 1942 2,378,068Eason June 12,1945 2,545,570 Caldwell Mar. 20, 1951 2,587,076 Verson eta1 Feb. 26, 1952 FOREIGN PATENTS Number Country Date 12,624 GreatBritain Sept. 1, 1888

